Mask-bot allows the research team at CoTeSys -- Munich's
robotics cluster of excellence -- to rear-project one of any number
of realistic faces onto a semi-translucent blank mask.
Because of the close distance between the high-compression fish-eye
lens and the mask, the face is bright enough to be seen outside in
daylight.

Mask-bot has been created as a cheaper and more flexible
alternative to creating robotic faces with dozens of small motors
manipulating the facial expressions.

The team believes that the system could be used in the future to
give robots realistic human faces which could change on demand. In
the interim, they see potential applications in video conferencing. Researcher Takaaki Kuratate explains:
"Usually, participants are shown on screen. With Mask-bot, however,
you can create a realistic replica of a person that actually sits
and speaks with you at the conference table. You can use a generic mask for male and female, or you can provide a
custom-made mask for each person."

If Mask-bot were to be used as a robot face, it would have to
work by converting a 2D image into the 3D mask projection, as
opposed to using a video feed of the person speaking -- as would be
the case in video conferencing. The team is working on a program
that allows the system to convert a two-dimensional photograph into
a correctly proportioned projection for a three-dimensional mask.
Further algorithms provide the facial expressions and voice.

The system has a huge library of face motion data collected
using motion capture. It then matches the relevant face movements
to the sounds that are spoken. Each of the facial expressions
corresponds to a set of coordinates that can be assigned to any new
face, thus bringing it to life. This is combined with emotion synthesis software which delivers the visible emotional
nuances to show if the robot is sad, happy or angry.

Mask-bot -- which you can see in action in the video above -- is
the result of collaboration with AIST, the National Institute of
Advanced Industrial Science and Technology in Japan.